Gavin Schmidt and "Uniquely" Oriented Speleothems

In our examination of the new Mann proxies, there is a notable increase in the prevalence of speleothem proxies in the MWP network.

Craig Loehle used a couple of speleothem proxies in his reconstruction. One was a grey-scale series from Holmgren’s Cold Air Cave, South Africa.

Not to be outdone, Mann et al used two series from Holmgren’s Cold Air Cave, using, however, two other series: C13 and O18.

The second spelothem series used by Loehle was a temperature reconstruction by Mangini on a European speleothem, which had an inverse orientation to the native dO18 series because Mangini ascribed a negative correlation between temperature and speleothem dO18, which Gavin Schmidt excoriated as follows:

As mentioned above, there are a priori reasons to assume d18O records in terrestrial records have a temperature component. In mid-latitudes, the relationship is positive – higher d18O in precipitation in warmer conditions. This is a function of the increase in fractionation as water vapour is continually removed from the air. Most d18O records – in caves stalagmites, lake sediment or ice cores are usually interpreted this way since most of their signal is from the rain water d18O. However, only one terrestrial d18O record is used by Loehle (#9 Spannagel), and this has been given a unique negative correlation to temperature.

However, Mangini’s speleothem record is no longer uniquely oriented, due to recent spelunking by Mann and associates.

The first figure below shows the orientation of the original dO18 data (positive dO18 is up and negative dO18 is down), the orientation advocated above by Gavin Schmidt.

In the case of the Dongge dO18 record, this is negative (as shown in the archived rtable) and the orientation of the series is accordingly inverted during the Mannian algorithm. Here is how the Dongge gridcell goes into the Mannomatic – obviously upside down from the original series.

So the orientation of the Mangini dO18 series no longer stands alone, joined now by the Mannian Dongge Cave dO18 series.

Schmidt concluded his discussion of the Loehle reconstruction, citing this and other issues, by aying:

What does this imply for Loehle’s reconstruction? Unfortunately, the number of unsuitable series, errors in dating and transcription, combined with a mis-interpretation of what was being averaged, and a lack of validation, do not leave very much to discuss.

Having examined details of the Mann study, I can confidently say that “the number of unsuitable series, errors in dating and transcription, combined with a mis-interpretation of what was being averaged, and a lack of validation” in the Mann study result in precisely the opposite: there is a great deal to discuss.

The parable urges us to remove the beam from our own eye before worrying about the mote in the other fellow’s eye. One feels that Schmidt and Mann should think about a similar policy: removing the uniquely oriented speloethem from their own reconstruction before worrying about the uniquely oriented speleothem in the other fellow’s reconstruction.

86 Comments

Having examined details of the Mann study, I can confidently say that “the number of unsuitable series, errors in dating and transcription, combined with a mis-interpretation of what was being averaged, and a lack of validation” in the Mann study result in precisely the opposite: there is a great deal to discuss.

For sure. The data handling and verification in Mann 08 is so haphazard there are no words for it. Proxies were removed without reasonable explanation and some which were used had even less. Standards they claimed to have for acceptance were not followed as far as I can tell (some of the accidentally published and rejected 1357 proxies look like they should be accepted) and proxies that were accepted were modified to fit pre-ordained conclusions

I just did a post on Dr. Loehles tree linearity paper. Something I read some time ago and was posted on here. I did a write up because as I learn the landscape of this science its nature is becoming more clear. I think it’s related to your post.

Re: Jeff Id (#1), Excellent post, Jeff. Thanks. The way I figure it, if someone really knows the material, they should be able to explain it clearly. Hawking even explained black holes in a popular book. Scorning the ignorant does not prove you are smart.

Can anyone please refer me to a simple, primary calibration graph where a relevant speleothem property is graphed against measured temperature? With error estimates? I’m not being lazy – one needs recommendation for such papers from people in the business because there are sometimes junk papers around. It is no longer so easy to use the Net to search for quality or seminal publications.

I thought it would be useful to give the end of the paragraph quoted from Gavin Schmidit’s critique of the use of the Mangini O18 series in the Loehle reconstruction:

However, only one terrestrial d18O record is used by Loehle (#9 Spannagel), and this has been given a unique negative correlation to temperature. This might be justified if the control on d18O in the calcite was from local cave temperature impact on fractionation, but the slope used (derived from a 5-point calibration) is more negative even than that. Unfortunately, no validation of this temperature record has been given. [Emphasis added]

If I understand this correctly, Schmidt said negative correlation of d18O records to temperature can be justified, but that Loehle had failed to do so, at least in the initial paper. Perhaps this issue was resolved in the Loehle correction.

DC, for better or worse, Loehle used peer reviewed temperature reconstructions as the authors presented them without doing his own Mannian calibration. Under his approach, it’s the job of the original specialists to do their job right. If Gavin Schmidt thinks that the original specialist screwed up, that’s his right. I obviously think that this sort of “auditing” has considerable value. Schmidt could very wll be right about the Mangini speleothem – I haven’t studied it and have no opinion on it. But then surely there is an obligation on someone in the speleo community to take issue with the Mangini study if that’s what they think. It’s not Craig’s job to try to resuscitate the Mangini proxy if it is invalid. Under his stated methodology, his obligation would be not to use it once issue was taken with it in the peer reviewed literature.

But could you please respond to the specific issue here: what’s sauce for the goose is sauce for the gander. If Schmidt objects to Loehle’s handling of the Mangini cave, then you must agree that that the same objection applies to Mann’s handling of the Dongge Cave. C’mon, it won’t hurt all that much to simply agree for once.

In the paragraph you cited, Schmidt’s objection to the Mangini cave proxy was that the slope was too negative (i.e. too steep) to be consistent with the implied mechanism of “local cave temperature impact on fractionation”. It’s not clear that the same objection applies to the Dongge Cave proxy. Do you have any evidence that it does? If so, then I might agree with you.

Of course there is at least one other objection to this proxy in Schmidt’s analysis.

Unfortunately, the Mangini et al (2005) speleothem record (Loehle #9) was tuned to a reconstruction of solar activity so that the warm periods lined up with solar peaks. This invalidates its use on that age model for any useful reconstruction, since it would be assuming a relationship one would like to demonstrate.

In the paragraph you cited, Schmidt’s objection to the Mangini cave proxy was that the slope was too negative (i.e. too steep) to be consistent with the implied mechanism of “local cave temperature impact on fractionation”.

Can you quote any other time that Schmidt objected to the Mangini cave proxy except in reply to Loehle’s reconstruction? Maybe perhaps when the original paper came out?

Also, was the Mangini et al (2005) cave proxy referenced in any other team paper? If so, what was Schmidt’s objection then?

#12. The Mangini series has not been used in Team reconstructions. In unrelated news, it has a prominent MWP.

#11. The difference in “tuned” and “untuned” Mangini data is not material to the present analysis. The differences do not exceed 10 years or so. So while you may find this sort of point “convincing”, it’s more of a debating point.

As I said above, I’ve not examined the Mangini proxy and have only recently looked at speleothem proxies. I have no personal opinion on the validity of this proxy. I take no issue with you or Gavin or anyone else parsing the validity of these proxies; if people are going to use these studies, then someone should be doing it. If there’s something wrong with the Mangini reconstruction, then it should be identified. And BTW why hadn’t Gavin or his speleo informant already publicized that alleged defect in the Mangini proxy so that we could know how Mangini defended his reconstruction. If there was outstanding professional controversy on the Mangini proxy, then, in my opinion, Loehle would have been obliged, under his methodology, not to use it until the professional controversy was resolved. It would not have been his job to try to develop his own specialist interpretation of a speleothem in Austria.

Did Gavin satisfy himself that the slope of the Dongge cave relationship was not “too negative” before rushing into print with fulsome praise of the latest Mann article? Of course not. Gavin didn’t even satisfy himself that the Tiljander proxies were not upside down. I don’t know whether Loehle should or should not have used the Mangini speleothem as a proxy. And I agree that due diligence on this decision is warranted. But it’s absurd that the climate science community should carry out fine-grained due diligence on Loehle, while failing to carry out the most elementary due diligence on any of the Team reconstructions.

Another point and this is an annoying one, as I’ve wasted time on it. The O18 control on speleothems (e.g. the Borneo discussion) is ascribed in the literature to O18 in precipitation, not to “local cave” mechanisms. Gavin’s comment about “local cave temperature impact on fractionation” as a possible mechanism is simply a red herring – perhaps a little fact checking at RC would be in order. This is made worse by your characterization of Gavin’s red herring in which you use the term “implied” mechanism. I do not believe that you have the slightest basis for supposing that this is the “implied” mechanism in Mangini (as opposed to O18 in precipitation which is not a “local cave” mechanism.)

Mann’s reported low-frequency correlation for the Dongge speleothem (which was said to be “significant”) was -0.52. The standard deviation of the smoothed dongge series (the relevant version for the low-frequency correlation) is 0.25 and of the relevant smoothed gridcell instrumental series is 0.21. Thus, the slope of the Dongge relationship in the paper so fulsomely endorsed by Gavin Schmidt is -0.64 dO18/deg C – a more negative relationship than the Mangini case.

Once again, these folks need to remove the beam in their own eye.

And DC, I hope you see the problem with how Gavin Schmidt presents this – at first blush, it appears “convincing” in your words. And here he is whining about “fact checking” in a San Francisco newspaper column, while failing to do so himself.

If you fail to do “elementary due diligence” on “stuff” you’re “related to”, you have no business doing any due diligence at all on anyone else, much less a “fine-grained-style type”. Such attempts to “play favorites” should be “dismissed out of hand” and ignored as “like totally bogus, dude”.

I don’t know whether Loehle should or should not have used the Mangini speleothem as a proxy. And I agree that due diligence on this decision is warranted. But it’s absurd that the climate science community should carry out fine-grained due diligence on Loehle, while failing to carry out the most elementary due diligence on any of the Team reconstructions.

For a good calibration study, take a look at the new science article by Zhang et al 2008. It is a fast-growing sample also from China. They have overlap with the instrumental record. Figure S4 in the SOM.

Steve,
I think the whole subject of O18-temperature relationship in speleothem proxies is more complex than either of us realized. In particular, Schmidt’s comments about the steep negative slope in Mangini appear to be inapplicable to monsoon region proxies.

Here is a passage that sheds some needed light on the topic.

7.4 Chemistry of speleothems
7.4.1 Dating methods

For mid- to high-latitude regions, the δ18Οp dependence on temperature averages +0.59 ± 0.09 ‰ per °C (Dansgaard, 1964; Rozanski et al., 1993). This positive dependence exceeds the calculated calcite-water fractionation at equilibrium (about –0.24‰ per ºC). As temperature usually has a larger effect on the δ18Οp than on the calcite-water fractionation, a positive correlation between temperature and δ18Οc should be expected in many mid- and high-latitude sites. Heavier δ18Οc has thus been taken to reflect warmer mean annual temperatures (Dorale et al., 1992, 1998; Gascoyne, 1992; McDermott et al., 1999, 10
2001; Paulsen et al., 2003). The tenability of the approach must, however, be tested for each site; for example the opposite relationship in north Norway was found by Lauritzen and Lundberg (1999).

The mechanism and thus the temperature-O18 relationship is different in monsoon-affected regions, though.

In many regions, it has been observed that the most intense rainfall have the lowest δ18Οp. Thus, in rainy periods or seasons the δ18Οc would reflect this “amount effect” on δ18Οp. This has been observed in monsoon regions, where the most depleted δ18Οc values correspond to heavier monsoon rain intensity (Fleitmann et al., 2003). A high correlation between high-resolution (annual) δ18Οc series from Oman speleothems and the residual 14C (Δ14C), provided well-constrained evidence of solar activity influence on the Indian Ocean monsoon (Neff et al., 2001; Fleitmann et al., 2003).

So, based on my understanding of the above information, it still is not apparent that Schmidt’s objection to Mangini applies to the Dongge Cave proxies, as the mechanisms involved are very different.

#17. DC, look, your assumption that Gavin had done any sort of due diligence on Mann’s speleothem is completely far-fetched, as is your assumption that the opportunistic relationships can be bailed out by some reference.

If you believe that the texts show that there is a negative relationship between monsoon-affected O18 and temperature (in order to justify Dongge), I’m quite prepared to accept such a relationship (for the sake of argument) – but you then need to invert the monsoon-affected Socotra speleo O18; also ShiHua Cave O18 just to the north of Dongge Cave; not to speak of the Dasuopu ice core O18, which is also derived form monsoon rainout.

MAnn’s stuff is a hodge-podge and, if you try to apply any sort of rational criteria, the balloon gets pushed out somewhere. Face it. Mann was just data mining for opportunistic relationships in speleothems, just as he does with tree rings. It’s a waste of your time searching for rational explanations – they aren’t there.

Re: Steve McIntyre (#19), so I take it you *didn’t* read the Zhang 2008 paper I mentioned in comment 16…
Steve: You take it wrong. I’ve read it. ACtually I read it a while ago. I’ve plotted Heshang and Dongge and some other O18 records on similar scales and will post on them some time.

Now this is getting interesting. If monsoonal d18O has a different sign than water from other climate types we have a type of proxy here that may actually change sign repeatedly in the same series.
It is well attested from historical sources that the summer monsoon in China extends further north during warm periods. So to estimate temperature from chinese speleothems you first need to know the temperature….

So to estimate temperature from chinese speleothems you first need to know the temperature….

A commonly accepted time-temperature relationship graph for the last two-thousand years is available within the peer reviewed climate science literature which should allow a reconstruction of the necessary data.

Tuned ages are established by tuning the 230Th timescale to the tree-ring carbon-14 timescale at 84 points.

This is what was said to have been done in the Mangini case as well. As far as I can tell, there’s not a speck of difference in the dating method used in the Mangini speleothem and the Dongge speleothem.

Most (~80%) of the rainfall in the region surrounding Dongge Cave occurs during the summer monsoon months (May-Oct). Rainwater collected at Guiyang, ~160 km northwest of Dongge Cave, has oxygen isotope ratios (VSMOW) which range between -3.4 per mil in the winter and -12.4 per mil in the summer. The Dongge Cave isotope record is therefore a proxy for Asian Monsoon intensity.

This is exactly the same pattern as Thompson’s Himalaya ice cores, also monsoon proxies: more negative in the summer time.

Dasuopu has a noticeable trend to lighter O18 in the 20th century – this is the heart of the Lonnie Thompson hockey stick.

But now we’re told that there is a “statistically significant” negative correlation between monsoon-driven Dongge O18 and temperature.

Excuse me if I feel like this is climate science by the Queen of Hearts.

and the Queen said severely ‘Who is this?’
‘Idiot!’ said the Queen, tossing her head impatiently; and, turning to Alice, she went on, ‘What’s your name, child?
‘And who are THESE?’ said the Queen, pointing to the three gardeners
The Queen turned crimson with fury, and, after glaring at her for a moment like a wild beast, screamed ‘Off with her head! Off—’
The Queen turned angrily away from him, and said to the Knave ‘Turn them over!’
‘Leave off that!’ screamed the Queen. ‘You make me giddy.’ And then, turning to the rose-tree, she went on, ‘What HAVE you been doing here?’
‘I see!’ said the Queen, who had meanwhile been examining the roses. ‘Off with their heads!’
‘Are their heads off?’ shouted the Queen.
‘That’s right!’ shouted the Queen. ‘Can you play croquet?’
‘Come on, then!’ roared the Queen,
‘Get to your places!’ shouted the Queen in a voice of thunder, and people began running
The Queen had only one way of settling all difficulties, great or small. ‘Off with his head!’ she said, without even looking round.
The Queen’s argument was, that if something wasn’t done about it in less than no time she’d have everybody executed, all round. (It was this last remark that had made the whole party look so grave and anxious.)
‘She’s in prison,’ the Queen said to the executioner: ‘fetch her here.’

I don’t see this as weird or “Queen of Hearts” science, given the various explanations of the geochemistry involved. But maybe Jud Partin can set us both straight.

The Zhang study is interesting though – among other things, it suggests a breakdown in the relationship between temperature and monsoon in the recent period: “The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century.”

“The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century.”

Oh, brother, more “divergence” problems, caused by some unknown factor. Sounds like dendroclimatology. Even about the same year of divergence! And there could be no explanation, but humans. Sound familiar?

“But ‘glory’ doesn’t mean a nice knock-down argument,” Alice objected.
“When I use a word,” Humpty Dumpty said in a rather scornful tone, “it means just what I chose it to mean, neither more nor less.”
“The question is,” said Alice, “whether you can make words mean so many different things.”
“The question is,” said Humpty Dumpty, “which is to be master, that’s all.”Lewis Carroll, Alice Through the Looking Glass

#26. The article is a fantastic new record from Wanxiang Cave, China that came out in Science 7 Nov 2008. You must have read it when it came out to have read it some time ago. The correlation between the stalagmite record of monsoon weakening and the fall of Chinese dynasties is pretty amazing.

What I am perplexed by though is the tone of your posts. Are you more interested in “Mann-bashing” and keeping visitors coming back to your site for chuckles or science? One would be hard-pressed to find the wording you use in any scientific literature. …just curious. Your posts don’t match up all that great against what you said when you visited GT.

#31. Judd, yes, I read it when it came out. I was planning to do something on speleothems but got sidetracked into Mann 2008.

I’m discouraged whenever I look at the stock market. So I’m definitely sour these days.

As to the tone wrt to Mann et al 2008, I’m not doing it to “Mann-bash”. I really hadn’t spent much time in the last year on Mann material; browse through my posting record. I would have preferred not to be dealing with this paper; but people obviously expect me to be familiar with it. It’s supposed to be the new thing. And one could not a priori assume that the methods were hopeless.

But there is very little of inherent interest in the article. Methodologically, it is almost total garbage and so it’s not much fun wading through it.

Adding to the pain, the code is a shambles and horrendously documented. They do some weird things that make no sense; and so it takes a long time to figure out some of the stuff even when you’re spotted the code. Plus the code is incomplete (though less incomplete than before). Some of these issues probably don’t “matter” unless you’re trying to replicate their method to benchmark for sensitivity, in which they do matter.

If you immerse yourself in the details of this paper, it honestly feels like it was done by the Queen of Hearts, except that there is one liberty after another taken by the authors.

As to post wording, I write on technical subjects to a large audience and so I sometimes try to have a little fun with plays on words and the like – which you wouldn’t do in a journal article. But I think that I’ve kept away – as promised – from slagging the climate science community for the sins of a few, even though I’m dismayed at their apparent inability to properly appraise this sort of work. I undertook not to paint with too broad a brush and I think that I’ve done so.

Anyway, when I finish working through Mann 2008, I’m sure that I’ll cheer up.

Re: Steve McIntyre (#32), I admit that I have not kept up with all of your posts. I had heard though that you have some speleothem posts, so I stopped on by. I’m up to my eyeballs getting ready to leave for the West Pacific again for a field mission – so I can’t stay long.

However, it is worth mentioning as a somewhat objective bystander that, in general, your posts come off more like a personal attack than a healthy scientific debate. You say “Mann said/did this” or “Schmidt said this”. Why not begin with a basic scientific argument like: if there is anthropogenic GHG forcing, it would be non-seasonal (year-round) and non-hemispherical. How would that show up in these speleothem records that have tracked summer insolation at 65N for the last 224ka (Wang et al Science 2008)? Then you could go on to discuss how a speleothem record should be included into a hemispherical average. Then you could critique others work objectively.

Starting off with a personal attack drives away the very people you say you want to include on your site. I saw a couple of times where the scientists you posted on got really angry with you, wrote a hot comment, and said they would never come back. To your credit, you have toned down the general bashing against all climate scientists. I thank-you for listening to mine and Julian’s comments. However, it would be more constructive scientifically if you were to not engage in personal attacks right off of the bat. I know that there is a long and bitter history between you and others, but two wrongs don’t make a right (since you seem to be one for proverbs on this post). Goofing on the people and comments made on your site would be like ducks on the pond – but I don’t do it b/c it wouldn’t accomplish anything constructive.

If you continue with your tone, don’t be surprised if more and more scientists don’t visit/comment on your site. I think that having an open site to the public such as yours populated by educated engineers and scientists is a good thing. There is opportunity for growth… if things are approached constructively. The internet is only growing, and the ways of science are continually evolving.

I gotta get back to getting ready for my trip. And on a lighter note, I think that the research sites in the West Pacific do not pass your Starbucks Hypothesis!🙂

We have here another contribution from a just-passing-through scientist that appears to have sacrificed bandwidth for potential scientific content to make comments on matters of protocol. It would appear that getting (some) scientists to this blog is not the problem, but getting (some) scientists here to contribute to the scientific discussion is another. Even to eek out a comment from (some) scientists on the question of how they evaluate the Mann et al. papers’ methodology has been an apparently painful and unsuccessful operation.

Let the paper and methodology analyses roll. In the meantime, it is difficult to see how a truly dedicated, confident and enthused scientist with a counterpoint would be put off by Steve M being Steve M. He is not mean or grouchy and is certainly approachable.

Jud Partin is noting my not reading his comments on Five Monsoons O18 Series before making my post. I was just in the process of pointing this out when I read his post. Jud makes some valuable points about conflating some cave identifications and does what, in effect, I see too little of from other just-passing-through scientists.

You nailed me good, Jud and I deserved it, but I would not judge others here and certainly not Steve M by my error. Anyway, if I had not been distracted by your protocol lecture, I would have read your posts with scientic content and noted that that scientist is welcome here anytime.

Very fortuitous/ironic post you made though. It is exactly what I was talking about. Sometimes the internet can be detrimental in how quickly it works. …maybe they should install something like Mail Googles here!

You were so quick to post a comeback to mine that you didn’t check all of the facts first. Luckily I have pretty thick skin. That’s what two older brothers and military college will get you! However, I would hazard a guess that many other scientists would not be so patient… they would get pissed, tell you off, and never come back. How does this blog respond when people do that???

you catch more flies with honey than with vinegar… that’s alls I’m sayin.

Re: Jud Partin (#33),
Jud, your comments are well stated. However, I must say that when I started reading both CA and RC a few years ago, jumping back and forth between the sites reading both sides and trying to understand the hockey stick issue, I was struck by how much meaner and nastier that RC was. Steve does make snide remarks sometimes, and I wish he would not, but I understand his frustration with the RC crowd, with their sloppy science, arrogance and obfuscation. I applaud Steve’s excellent work, and his willingness to put his work in front of everyone to critique. I wish the RC folks would do the same. If so, they’d become better scientists.

Re: James (#40), James, the goal of realclimate and climateaudit are very different. Real Climate is run by climate scientists who are acting socially responsible and educating the public about climate science. The Internet is making the dissemination of information possible to a broad audience by cutting out the middle-man of the media. While the site does not replace the education one would receive on the subject, it gives great overviews of complex climate issues to the public. As such, I’m sure that they are constantly under attack from many people. I know I wouldn’t have the patience to run that site and keep repeating myself over and over.

Climate Audit wants to audit the methods and results and make sure that the people who are reporting their findings in climate science are correct. If you couple that with unconstructive language (by the both the moderator and posters), then most of the scientists who are mentioned here (or analogous sites) will feel like they are under a witch hunt and will react accordingly. You must see that, right? Who would be receptive and warm to an IRS auditor who bangs on your door one random day and demands to see all of your receipts, etc. You would only cooperate b/c the law demands it…

Now, if a scientist asks another scientist for their data to check something or to compare results, then cooperation is the norm. Hence my question to Steve if he either wants to keep feeding his CA readers or do science and publish papers??? Oh, and publishing papers is putting your work out there for all to critique…

Who would be receptive and warm to an IRS auditor who bangs on your door one random day and demands to see all of your receipts, etc. You would only cooperate b/c the law demands it…

Regardless of the demeanor of the auditor, if you had something to hide, you would perhaps be inclined to be secretive and not release all documents that the law is legally entitled to. Somewhat similar to the type of behavior that is exhibited by some “socially responsible” scientists who are less than responsive to FOI requests?

Real Climate is run by climate scientists who are acting socially responsible and educating the public about climate science. The Internet is making the dissemination of information possible to a broad audience by cutting out the middle-man of the media. While the site does not replace the education one would receive on the subject, it gives great overviews of complex climate issues to the public.

Jud, most participants here know what RC is about. They do provide some explanations and information about climate science, but what you call socially responsible, I would call an obvious intent to advocate policy. I see the science and policy getting a bit too friendly for my comfort when they attempt to sell it as straight science.

If one is looking for more seriousness, less personality and lots of policy oriented material advocating for immediate mitigation for the potential effects of AGW that is mixed with climate science information and explanations, I would strongly advise them to go to RC.

What was RC’s initial purpose? It appeared to be defending that which you will apparently not discuss.

Re: Jud Partin (#42), Jud, I think McIntyre’s “unconstructive language” is counterproductive, and I too wish he would publish more. But putting all of his analysis on the web along with his programs and methodology, and advancing knowledge and understanding, is science is a pure form. You don’t have to publish in a journal to make an important contribution. On another topic in your comment, the different goals of RC and CA does not excuse RC’s “unconstructive” behavior. Indeed, being an American taxpayer I think RC should be the epitome of politeness, discretion and honesty, but that too often is not the norm there. (And not just to SM. Check out Gavin’s treatment of Roger Pielke, Sr., and others with whom he disagrees.) It seems to me that the reason why Steve has been so poorly treated by RC is not his demeanor, but rather their irritation at the demolition of the HS by M&M, and his continued critiques of its resurrections along with his demonstrations of the sloppiness of the Team’s science. On the other hand, maybe it’s just because he does not totally accept their work without question. McIntyre’s work checking out the claims of climate scientists is as socially responsible as those educating the public (or, as Fritsch says, advocating policy), especially because of the importance of these issues. Finally, I think your description of an IRS auditor banging on the door in the middle of the night is a mischaracterization. Steve’s initial enquiries for data have seemed polite, and the responses by some have sometimes been clearly unprofessional. In my experience, those who hide data almost always do so because the data is detrimental to their case.
Let’s argue no more. We’d both like McIntyre to be a perfect gentleman, and to publish more, but I relish what he’s accomplished. I welcome your presence on CA, and your discussions of the work.

Re: Jud Partin (#42), Jud: the idea that sharing data is the norm may be true in some fields, but not in climate science. Poor archiving, secrecy are the norm in the climate reconstruction area (and see Santer links here as well, and IPCC hiding reviewer comments). It is not only Steve who has asked for data but other scientists as well. If they are not part of the inner circle, forget it. CRU won’t release their list of stations used to create one of only two world temperature records, nor the code by which they compute the output. GISS only released the code last year and the computation of station adjustments (among others) is pretty strange and arbitrary (and unproven to be correct). The CIA should be as good at keeping secrets.

Had you read all, or at least several, of Steve M’s posts, it would be clear to you why he speaks of Mann and Gavin in the tone that he does. When Steve speaks of his pre Climate Audit professional experience, reviewing other’s mining data, they generally fit into two categories, those that disclosed, and those that hid.

Furthermore his experience tells him that those that hid did so for good reason, they had something to hide. And those that disclosed did so for good reason, they had something to be proud of.

Many in the Climate Science community have hid when Steve inquired. From what Steve has released of his initial inquiries, they are professional, polite, and reasonable.

It’s a pretty simple equation. When Steve M sees the wagon’s circling, it just drives him to dig into it. When he digs into it, he generally finds something worthy of them hiding. When he posts their shortcomings, the authors don’t respond well. That’s their problem, not his. In turn Steve is a little flippant when he addresses their next claims. No need to chastise Steve, they asked for it.

I will, also, without allowing a grin to change my countenance, note that the article has 17 authors/coauthors and refers in the abstract to this revelation:

The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century.

I will bite my lip and say 10 times I am scientist; well, at least, I can say I was a scientist.

It is kind of an insider joke and if I have to explain it to you it would ruin it. Anyway I am well into reading the article I noted above and in no mood for frivolity.

But since you asked nicely, the 17 authors goes to a recent 17 author paper analyzed here (Santer et al. (2008)) from which Steve M requested information and from the replies he received, I suspect that some and perhaps a number of these authors were not familiar with some of the critical data in the paper. There was an ensuing discussion about how much coauthors contribute to a paper and especially when the number becomes large.

The reference to the anthropogenic switch of a temperature proxy in almost the exact time period as the China cave goes of course to the “divergence problems” of the tree ring and MXD proxies which has been discussed at length here at CA. This in turn goes to a number of discussions here at CA where it has been judged that perhaps more evidence should be presented for these rather general and vague conjectures to explain temperature proxies and even like the O18 inversions.

And now that I think about it, is not very funny, so I once again apologize for making a joke of it.

Now, if a scientist asks another scientist for their data to check something or to compare results, then cooperation is the norm. Hence my question to Steve if he either wants to keep feeding his CA readers or do science and publish papers???

IIRC, scientists HAVE asked other scientists for their data to “check something or to compare results”, only to be rebuffed (rudely, in some cases.)

Sharing data is NOT the norm in climate science.

Oh, and publishing papers is putting your work out there for all to critique…

Steve HAS published (and gone through the critique mill.) There are some scientists, however, that feel their papers are immune from critique (refusing polite requests for data and code, getting advice from lawyers not to post data, etc).

If the work you do is solid, then you’d welcome people to look at and possibly replicate your studies. Maybe they’ll find something that you missed, or create an easier code to support the same thing.

Maybe this is the first time I have seen scientists publish papers where the relation between two main variables can be positive or negative at will. That indicates to me an immature state of development, which further indicates that publications should be full of qualifications and not assertive or brashly deductive.

With speleothems and carbon isotopes, we have at least non-CO2 carbon in air in the atmosphere, air in the cave, CO2 in the atmosphere, CO2 in the cave, calcite and related minerals in the solid phase, calcite precursors in the liquid phase adjacent, carbon in cave lakes sometimes.

We have, at least, oxygen isotopes in air, CO2 and other atmospheric gases like NOx. We have them in rainwater, the seas/lakes etc that are the souce of the rainwater, in groundwater, in water proximal to calcite deposition, in calcite and related minerals.

We have fractionation in the biomass which decays and produces soluble isotopes that might end up in the speleothem.

We have mobility, mineral phases, fractionation, lagging, unpredictability of paths of gases and liquids and limited, good correlation data.

The multiple ways in which these factors can be combined is complicated by an uncertain relation between (say) oxygen isotope ratios and temperature. Many fractionation mechanisms are qualitative as observed, but quantitative by the time they are published, maybe with the help of circular logic to tie down temperature.

Example. There was a spate of reversing car accident claims – people put foot on throttle instead of brake. No amount of evidence would convince some they were in error. Of course, one outcome gives a positive correlation with speed, the other a negative, but what the heck, we can reverse the graph to fit the story.

Like many others, I welcome the chance for science to reconstruct the past with confidence. I am dismayed when methods fail after early promise (like dendrothermometry). That chance will not be realised by poor science that does not stand audit, even when raw data are graciously supplied.

I purchased and read a copy of the Zhang et al. (Nov 2008) Science article based on the superlatives that Jud Partin expressed about its proxy record. Like other posters here the paper appeared to me to hardly represent an example of hard science, but does probably, as claimed, show optimum conditions in a cave climate for tracking monsoon history. I suspect that might have been what the superlatives were all about.

Anyway cutting to chase on using O18 for a temperature proxy in recent times, I excerpted a two graphs from the SI below. It shows an anti-correlation of precipitation with O18 and a positive correlation with temperature after the 1960s, i.e. 1970-2003, but an anti-correlation for a 20 year period prior. The SI had the annual O18 data but not the Wudu temperature data and I thus was unable to check how the correlations were determined and the value of the pre-1970s temperature O18 anti-correlation. I will attempt to do that later.

I suspect the time period was determined by the availability of the Wudu station temperature data. The switch from a negative to a positive correlation would, in my mind, pretty much show that the O18 was not a good proxy for temperature and would require more than the conjecture about AGW effects in the reversal to change that view.

The precipitation correlation (shown in the left graph below) appears more consistent during the 50 year time period and I get this vague feeling that the authors would claim the cave data as a precipitation proxy but not a temperature one (or at least in its current form). If taken at face value the most recent post-AGW would stand as is for a temperature proxy, but the pre-AGW would have to be inverted and spliced. I think that would only show the complex nature of the relationship of O18 with temperature and I am not sure how this partial inversion would relate to the historical markers the authors used. It does, however, if fully appreciated, counter the proposition that the O18 historical traces are showing past climates hotter than present.

Re: Kenneth Fritsch (#50), either you didn’t read the small analytical errors associated with the record, or do not have enough experience to put them into context. …It should be obvious that the record is an outstanding scientific achievement.

Second, the authors show that the stalagmite d18O record agrees well with the historical drought/flood index, correlates with solar modulation (R = –0.33, n = 345 data points for the past millennium), and is negatively correlated with Chinese air temperature taken from a fully coupled GCM with solar and volcanic forcing (r = –0.46 and n = 345) data points.

Then post-1960’s, the stalagmite record is still negatively correlated with precipitation (R = -0.64 n = 48), but is now positively correlated with temperature (R=0.8).

The authors say that the forcing switched from “from natural to anthropogenic around 1960”. Not just “AGW” as you say. They give a range of possibilities: “Possible mechanisms include differences in the nature of solar versus greenhouse forcing, the effect of anthropogenic black carbon on the AM, and/or the effect of anthropogenic sulfate aerosols.” They then go on to address each of them.

Jud, I can read and evidently you did not understand my comments. I assumed what you were reporting as “fantastic” work was the technical part of it in the dating and temperature resolution – I’ll call that the hard science part. You are correct that I am not experienced at this point in passing judgment on that part of the paper, but then again that was not my main interest in it.

I find some of the other parts of the paper less than hard science and particularly so the reversal of temperature versus O18 relationship circa 1970. The anthropogenic effects are put forth as conjectures. What would cause the sudden reversal depicted in the graph?

An r =-.33 gives an R^2 = 0.11 or indicating that solar modulation explains about 11 % of the O18 response and r = -0.44 explains 21% of the O18 response.

Jud, can you locate the Wudu temperatures used in this paper? Are the correlations made by using annual data or the data from the 5-points running means?

Steve: Wudu is in GHCN/GISS – needless to say, only up to 1990 as this is one of the stations that NOAA and NASA have lost track of.

Debra Saunders is a conservative columnist for the San Francisco Chronicle who has a history of writing misleading contrarian pieces on climate change. She contacted NASA Public Affairs recently for a comment on the initial glitch on the October GHCN numbers (see this earlier post for discussions of that). They forwarded the query to me and since her questions were straightforward, I answered them as best I could. Indeed in her subsequent column, she quotes me accurately and in context. However, the rest of her column shows none of the same appreciation for basic journalistic standards.

Michael and Gavin:

Much in the spirit of the Fraser Institute’s damp squib we reported on last year, S. Fred Singer and his merry band of contrarian luminaries (financed by the notorious “Heartland Institute” we’ve commented on previously) served up a similarly dishonest ‘assessment’ of the science of climate change earlier this year in the form of what they call the “NIPCC” report (the “N” presumably standing for ‘not the’ or ‘nonsense’). This seems to be making the rounds again as Singer and Heartland are gearing up for a reprise of last year’s critically…er…appraised “Conference on Climate Change” this March. Recently some have asked us for our opinion of the report and so we’ve decided we ought to finally go ahead and opine. Here goes.

Rasmus:

Confusion has continued regarding trends in global temperatures. The misconception ‘the global warming has stopped’ still lives on in some minds. We have already discussed why this argument is flawed. So why have we failed to convince ?

Gavin:

As many people will have read there was a glitch in the surface temperature record reporting for October. For many Russian stations (and some others), September temperatures were apparently copied over into October, giving an erroneous positive anomaly. The error appears to have been made somewhere between the reporting by the National Weather Services and NOAA’s collation of the GHCN database. GISS, which produces one of the more visible analyses of this raw data, processed the input data as normal and ended up with an October anomaly that was too high. That analysis has now been pulled (in under 24 hours) while they await a correction of input data from NOAA (Update: now (partially) completed).

Group:

We discuss climate models a lot, and from the comments here and in other forums it’s clear that there remains a great deal of confusion about what climate models do and how their results should be interpreted. This post is designed to be a FAQ for climate model questions – of which a few are already given. If you have comments or other questions, ask them as concisely as possible in the comment section and if they are of enough interest, we’ll add them to the post so that we can have a resource for future discussions. (We would ask that you please focus on real questions that have real answers and, as always, avoid rhetorical excesses).

Eric:

I often receive letters that range from amusing claims that we are overlooking changes in the magnetic field, to tales about how the “weight” of carbon dioxide keeps it “near the ground”. If the writer sounds serious, then I treat them seriously, and do my best to provide a helpful reply. Often, though, I find myself in a pointless debate of the most basic, well-established physical principles. I generally cut off the discussion at this point, because I simply don’t have the time. This can result in a hostile response accusing me of “having an agenda”. Most would call me naïve for bothering to respond in the first place.

Eric:

I had the opportunity to attend a three-day meeting of the Nature Conservancy last week in Vancouver. I was there with my RealClimate hat on, to offer ideas and insight on blogging in particular, and public communication of science in general.

Gavin:

Many readers will remember our critique of a paper by Douglass et al on tropical tropospheric temperature trends late last year, and the discussion of the ongoing revisions to the observational datasets. Some will recall that the Douglass et al paper was trumpeted around the blogosphere as the definitive proof that models had it all wrong.

#53, #54:
Kenneth, my understanding is that the relationship between O18 and precipitation is unchanged. It’s not a change in “temp vs O18” that needs to be explained, but rather the sudden negative correlation between precipitation and temperature, which is presumably unprecedented in the instrumental record.

Jud, can you locate the Wudu temperatures used in this paper? Are the correlations made by using annual data or the data from the 5-points running means?

Steve: Wudu is in GHCN/GISS – needless to say, only up to 1990 as this is one of the stations that NOAA and NASA have lost track of.

According to the note to the figure in Ken’s earlier post #50, Wudu is 15 km NW of Wanxiang cave. Despite its having disappeared from GHCN’s sight in 1990, the figure shows data for it up to 2000 or so, and the post-1990 portion is the source of the strong positive correlation between d18O and temperature after the 1960s.

Unfortunately, I haven’t been able to take a look at the Zhang paper yet, as I am not at my office computer.

I have a source for Wudu temperatures from Sept. 1956 to present but the data is not in good form for efficiently downloading. The station number I found for Wudu is 560960. If I find no more convenient sources, I may combine the GISS data and my source data.

I was finally able to locate the temperature data for the Wudu station 560960 as noted in Zhang et al. (Nov 2008). I used the GISS data from here from 1944-1990 and the data from this source from 1991-2003.

I used the average annual temperature data to regress against the O18 data listed in the Zhang paper SI. I regressed over the time periods 1952-2003, 1952-1970 and 1971-2003 and graphed the results shown below in the first 3 graphs. I did a rendition of the graph shown in the Zhang SI by plotting the annual O18 and Wudu station temperature data over the period 1952-2003. It is presented below as the 4th and 5th order of appearing graphs. Finally, in light of the claims made for correlation of the O18 versus the NH temperatures (qualitatively) in the Zhang paper, I regressed the GISS instrumental annual average temperatures against the O18 measure for the period 1880-2003.

The O18 data does not have readings for every year with the following years missing from 1880-2003: 1884, 1886, 1891, 1893, 1896, 1899, 1902, 1905, 1907, 1910, 1913, 1916, 1919, 1922, 1925, 1928, 1931, 1934, 1937, 1940, 1944 and 1973.

The most important point that these regression graphs address is that all of the graphs, regardless of R^2 value, are in direct opposition to the relationship that the Zhang authors propose for their making qualitative indications of historical temperature changes. The authors point to the change in the relationship around the 1970 time period as a reversal and a visual inspection does indeed reveal a change at or near that point. However, when the regressions are available for these segmented periods from 1880-2003, it would appear that the O18 versus temperature relationship is reversed over the entire time period. This would appear to be counter to the Zhang paper authors’ contention that this reversal has an anthropogenic basis that started within the past 50 years. Of course, the main claim of the paper and the “calibration” period for O18 to precipitation indicates that the O18 provides a proxy for monsoon activity. I judge that the link to temperature from monsoon activity is not necessarily constant over time, the recent anthropogenic effects notwithstanding.

It would appear, in my view, that a lasting “natural” relationship between O18 and temperature that is suddenly overtaken by anthropogenic effects and then provides, almost serendipitously, a significantly better correlation, albeit reversed, than the old natural one, would require some hard evidence.

The O18 versus temperature regression plotted below for the time period 1971-2003 had an adjusted R^2 = 0.39 and a lag 1 auto correlation = 0.25.

Re: Kenneth Fritsch (#58), I lack a lot the statistical prowess that many on this site have. A question to you regarding your calculation: you did a year-to-year regression between the air temperature and stalagmite d18O. However, there is error associated with the stalagmite age model (unlike the temperature record that was written down by a human). How would one account for the error in the stalagmite ages when doing the regression you did?

However, there is error associated with the stalagmite age model (unlike the temperature record that was written down by a human). How would one account for the error in the stalagmite ages when doing the regression you did?

I think the error you refer to is the plus/minus uncertainty in the model determining the year. From the Zhang SI we have the following description of the dating error:

Errors are small, ±1 to ±5 years (2σ), due to high uranium concentrations
(from 5.8 to 10.8 ppm) and low initial thorium contents. The error in assigning a date to a
particular oxygen isotope value is about 15 years because of the uncertainty in relating
the position of the sub-sample used for dating to the position of the sub-samples used for
oxygen isotope analysis. Linear interpolation between dates has been used to establish
the chronology. 703 sub-samples, collected on average of every 0.16 mm along the
central growth axis, were measured for stable isotopic composition on a Thermo–
Finnigan Delta Plus Mass Spectrometer at Lanzhou University, China, with an analytical
error of ±0.1‰ for δ18O values, giving a δ18O record with an average resolution of 2.5
years over the past 1810 years (Fig. 1 and Table S2).

Perhaps, Jud, you could be so kind to provide us with your judgment on what this description means to you. The authors of Zhang in Figure S4 in the SI (that I reproduced above in Post #50) present data for individual years using 5-points running means “to eliminate possible offsets in year to year correlations”. Apparently the 5-points running means were not used there for any problem associated with the dating error.

I do want to look at trend slopes for the 1880-2003 time periods using what I think the authors mean by a 5-point average, as I suspect that process would not “flip” the O18 to temperature relationship to that assumed by the authors in depicting qualitative temperature changes in the longer term past.

Kenneth, I suspect that you did a fair bit of work to collate Wudu data from that URL. Here’s another method that might be easier if you notice that there is daily information. Look up the station id directory athttp://www1.ncdc.noaa.gov/pub/data/ghcn/daily/ghcnd-stations.txt
where you will determine that the id for Wudu is CH000056096. Then do the following:

Steve, thanks much for the reminder. I went through those steps and I now have the the Wudu data for the time period 1951-2008 for temperature and precipitation. I need to do the regressions with precipitation corresponding the temperatures ones I did.

If I had initially gone to the Station Data thread listed on the left of the page above and remembered that GHCN has daily data that has not been compiled into monthly, I would have saved myself some time.

Ken —
Well done! I hope you consider a letter to Science pointing this out.
Are the correlations significant after the Quenouille effective sample size adjustment? (It’s not very fancy, and assumes regularly spaced data, but would be adequate for this job and a lot better than the Newey-West HAC adjustment currently popular in economics.)
Zhang’s SI Figure S4 makes the recent correlation look a lot stronger than it really is by omitting 2001-03 (where d18O fell dramatically), and by plotting the 5-point running means.
Is there a GISS subseries for China or this locality? That would be interesting as well.
Also, what happens when you use the Wudu data back to 1944? It looks pretty warm, and so may alter the correlations.

I am strictly an amateur who appreciates learning from the pros at CA, such as you. I like to involve myself with these calculations knowing that if I post them here my most ergregious errors can be corrected and I can learn. I have no ambitions at this point in my life beyond trying to learn.

The GISS temperature data for 1944, 1945 and 1946 is complete, but there is no O18 data for 1944. The years 1948 and 1949 have no GISS temperature data, while 1950 is missing 2 months worth of data and 1947 and 1951 have one month of missing data each.

I did not want to do any “infilling”, but if the complete years 1945 and 1946 are added to the 1952-2003 and 1952-1970 time periods the R^2 values go from 0.00 to 0.10 and 0.31 to 0.29, respectively.

Using the lag 1 auto correlation correction, the trend for O18 versus temperature remains statistically (p equal or less than 0.05) above zero.

I would like to make some comparisons with other nearby Chinese weather stations – if I can find them.

I looked at the data for wudu from the source which Steve indicated. I think there might be a substantial error for December, 1990. the value is the only negative temperature in the entire record (at -4.81). My suspicion is that it is a simple sign reversal.

Here are the original records from GHCND. I think that you’re right, but the screwup is in the daily data. I guess that NOAA’s “rigorous” quality control was unequal to this.

[1] “CH000056096199011TMAX 178 I 209 I 220 I 223 I 230 I 211 I 183 I 161 I 159 I 173 I 176 I 186 I 188 I 205 I 198 I 176 I 161 I 170 I 152 I 174 I 125 I 98 I 116 I 176 I 144 I 157 I 159 I 156 I 128 I 56 I-9999 ”
[2] “CH000056096199011TMIN 133 I 122 I 112 I 122 I 126 I 116 I 135 I 88 I 38 I 35 I 50 I 54 I 57 I 72 I 55 I 99 I 117 I 124 I 121 I 70 I 83 I 71 I 84 I 60 I 90 I 38 I 34 I 71 I 14 I -15 I-9999 ”
[3] “CH000056096199011PRCP 0 I 3 I 0 I 0 I 0 I 0 I 2 I 0T I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0T I 0 I 0 I 0T I 0 I 0 I 0 I 54 I 0 I-9999 ”
[4] “CH000056096199012TMAX 5 I 6 I 0 I 38 I 90 I 78 I 33 I 69 I 107 I 79 I 60 I 67 I 75 I 75 I 47 I -6 I 74 I 126 I 73 I 83 I 37 I 24 I 51 I 47 I 49 I 78 I 77 I 79 I 103 I -5 I -73 II”
[5] “CH000056096199012TMIN -174 OI -131 I -150 OI -195 OI -180 OI -156 OI -135 I -153 I -155 I -149 I -126 I -133 I -136 I -106 I -154 I -137 I -169 OI -131 I -131 I -160 I -110 I -165 OI -171 OI -166 OI -162 I -164 OI -166 OI -155 I -154 OI -134 I -119 I”
[6] “CH000056096199012PRCP 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0T I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 3 I”
[7] “CH000056096199101TMAX 79 I 68 I 63 I 84 I 95 I 88 I 102 I 93 I 47 I 89 I 94 I 79 I 55 I 64 I 72 I 98 I 102 I 116 I 95 I 80 I 108 I 84 I 59 I 61 I 95 I 87 I 72 I 80 I 82 I 64 I 75 I”
[8] “CH000056096199101TMIN -1 II 26 I 2 I 9 I -19 I -22 I -21 I -2 I 27 I 22 I -16 I -14 I -6 I -32 I -35 I -21 I -11 I 42 I 20 I 54 I 34 I 38 I 33 I 20 I -16 I 40 I 44 I 24 I 44 I 20 I 21 I”
[9] “CH000056096199101PRCP 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0 I 0T I 0 I 0 I 0 I 19 I 0 I 0 I 0 I 0 I 0 I 0 I 0T I 0T I 23 I 5 I 0 I 0 I 0 I 0 I 0 I 0T I 20 I 0 I”
[10] “CH000056096199102TMAX 57 I 69 I 82 I 103 I 72 I 112 I 90 I 92 I 117 I 129 I 105 I 68 I 67 I 110 I 112 I 116 I 78 I 89 I 77 I 120 I 97 I 136 I 157 I 153 I 171 I 170 I 153 I 118 I-9999 -9999 -9999 ”
[11] “CH000056096199102TMIN 26 I 8 I 27 I 22 I 45 I 37 I 47 I 52 I 18 I 36 I 63 I 50 I 45 I 44 I 15 I 37 I 49 I 38 I 18 I -1 I 41 I 14 I 20 I 35 I 29 I 70 I 90 I 42 I-9999 -9999 -9999 ”
>

I have nearly completed my 5-point average of the O18 measure by averaging the O18 point in question with the 2 points above it and the 2 points below it. Unlike the authors of the Zhang paper, I do not do the same with the annual temperatures because as Jud Partin notes the guy recording the GISS temperature data does not make +/- 2 year errors.

I may do the Zhang authors’ rendition of complete 5-point averaging as a check on whether I can duplicate their graphs.

Re: Kenneth Fritsch (#70),
One thing that occurs to me is that the isotope results may already be smoothed in the sense that the sampling interval covers more than one year. I understand that the samples were prepared by scratching the calcite growth layers with a knife and collecting the powder. Depending on the size of the scratch then this may cover several years growth.

If you are averaging the isotope signal shouldn’t you also average the temperature signal for a true comparison.

I understand that the samples were prepared by scratching the calcite growth layers with a knife and collecting the powder. Depending on the size of the scratch then this may cover several years growth.

If you are averaging the isotope signal shouldn’t you also average the temperature signal for a true comparison.

My planned next step was to look at averaging both O18 and temperature. The technique used to obtain the O18 value would, as you indicate, weigh on how the data is treated. I guess we would need a meeting here of the technical and statistical minds as to what we are actually looking at and what information can be derived from a statistical treatment of that data. I am not qualified in either area, but I can do grunt work or provide what I have to someone more qualified.

What I suppose confuses me is that the O18 data is reported for individual years. What you describe as technique would seem to indicate that the results would more properly be reported for a range of years. I suspect that it was reported the way it was because the sample has some “central” tendency for a given year.

It is difficult for me to see where the trend calculations are going to change direction (the point of my analysis) by doing more averaging, but instead of conjecturing, I will do additional regressions with 5-point average for O18 and temperatures. Or are you suggesting the a 5-point average of the temperature data be used against the O18 values reported for individual years?

Re: Kenneth Fritsch (#73),
Kenneth. they say there are 703 d18O analyses with an average resolution of 2.5 years. By this I take it that each sample covers 2.5 years of growth. The reported ages probably represent the central age of each sample.

Mark T, I agree that scratching is not the best way to obtain a sample. I’m assuming this is the method they used though they don’t say. It is intriguing that the paper in Science does not cite:

The WX42B stalagmite was halved lengthwise and subsamples were collected along the growth axis for O-C isotope
analysis by scraping surface using a knife. To avoid cross-overlapping of subsamples, alternative subsamples
were selected for analysis[17]. Four layers with clear growth lamina were selected to do the Hendy test.

It’s difficult to imagine taking 700+ samples from a 120mm long speleothem by scratching. I would prefer to have used a computerised milling system in which you can control precisely the path, width and depth of milled channels in a sample.

This paper shows the correlation between precipitation amount and d18O for Wanxiang using both smoothed and unsmoothed data. Smoothing dramatically increases R from -0.3 to -0.64!

Re: Paul Dennis (#71), Ouch. That wouldn’t really qualify as smoothing since such an unscientific, i.e., not repeatable (how do you scratch to the same depth every time?), method would introduce more error, which sort of defeats the purpose of “smoothing.”

As noted in my previous post, I have calculated what I assume to be a 5-point average for all the O18 measures (as employed by the Zhang authors) and regressed those values versus the annual GISS temperature data for Wudu and the NH.

The first set of regressions was made for the Wudu temperatures for the periods 1952-2001, 1971-2001 and 1952-1970 and called RW1 below. A second set of regressions (RW2) was made for the Wudu temperatures using the periods 1952-2001 and 1952-1970 and by adding in the 1945 and 1946 data. A third set of regressions (RW3) was made for the Wudu temperatures using the period 1952-2001 and adding in the 1945 and 1946 years data and the incomplete 5-point averaged years 2002 and 2003 and using the period 1971-2001 and adding in the incomplete 5-point average years 2002 and 2003. Finally the O18 5-point averages were regressed against the NH temperatures over segments of the period 1880-2001 as noted below in RNH.

The Wudu temperatures in the regressions are in degrees C and for the NH temperatures anomalies in 100ths of a degree C were used.

Using the 5-point average for O18 (to perhaps accommodate the dating uncertainty) does not change the positive trends that continue to show up in these regressions. Without further evidence, in my judgment, these results point away from the O18 versus temperature reversal in the instrumental era from that qualitatively indicated for historical times by the Zhang authors having a significant anthropogenic basis.

I repeated my regression analyses from above for O18 versus Wudu and NH temperatures using the 5-point averages for both the O18 and the temperature values.

I included the incomplete 5-point averages from the end point years of 1880, 1881 and 1952, 1953 and 2002, 2003.

The results presented below show the same trends as prior analyses, where temperatures and O18 for individual years were used, and, where temperatures for individual years were used with 5-point averages for O18. The interferences from the results would therefore not change by averaging.

Note also that the R^2 of 0.62 for the period 1971-2003 for the regression O18 versus Wudu temperatures is in good agreement with the Zhang authors for that approximate time period (R =0.8).

O18 versus Wudu temperatures using 5-point averages for both O18 and temperature:

After more closely looking at the temperature and precipitation data extracted from the GHCN (daily Wudu), GISS (monthly Wudu) and TuTiempo.net, I found that the years 1968 and 1999 (for the time period 1952-2003) should be excluded due to my inability to locate complete data at either of the three links below. Note that the year 1974 is excluded due to the lack of O18 data for that year in the Zhang paper.

I had reported the data as the Zhang authors did in their paper using a 5-point average (average of the point of interest plus the 2 above and 2 below). I did not adjust the slope standard deviations as I was unsure how to properly do that with the 5-point averages used. As a matter of convenience, I went back and determined the lag 1 correlation of the regression residuals and adjusted the slope standard deviations using the techniques used in Santer et al. (2008). I show all the pertinent regression values and the adjusted slope standard deviations for each regression below. The Wudu precipitation data was used in units of meters of rainfall, the Wudu temperature was used in degrees C and the NH temperatures were anomalies in degrees C.

The adjusted standard deviations show that, in all cases except one (including the O18 versus NH temperature over the 1880-2003 time period), the regression slopes are not statistically different than 0 (p equal or less than 0.05). The only regression that did not include 0 in its 5%-95% CI was the O18 versus Wudu temperature for 1952-2003 and that CI almost touched on 0.

If the lag 1 residual adjustment for the slope standard deviation is properly applied here and with the dating uncertainty in mind as noted by the Zhang authors, my simple-minded analysis would indicate that going beyond a qualitative statement about the relationships of temperature and precipitation to the O18 values in the Zhang paper would be a stretch.

Re Kenneth Fritsch, #70, 72, 76, etc,
I assume that by “trend” you mean the slope obtained in a regression of dO18 on temperature? “Trend” usually suggests a time trend, ie the slope obtained in a regression of something on time itself.

The Wudu temperatures in the regressions are in degrees C and for the NH temperatures anomalies in 100ths of a degree C were used.

It’s a little confusing to use these different units in your regressions, since it causes an apparent change of two orders of magnitude between the response to Wudu temperature and NH temperature. NH temperature should have a somewhat muted effect, but this is pretty extreme!

The only reason that NH temperatures are sometimes measured in .01dC units is that using 80-column 1960s-vintage punched card computer technology, if you didn’t drop the decimal point, you lost a valuable digit of precision. Today that’s no longer relevant, but bureaucracies are slow to change their ways…

On this blog it doesn’t much matter, but when you write up your letter to Science and accompanying SI refuting Zhang et al’s orientation, you should use consistent units of dC.

Hu, I considered converting so that the units are comparable and I usually do, but I have been rather lazy lately and thought that the note on the units would suffice.

I have absolutely no desire to publish a letter on this matter or most others. If anyone wanted to work it up into a letter they are welcome to any material I have. I doubt very much that the point I am attempting to make here would be deemed important by the editors.

I have searched the GHCN data sets for temperature records near the Wudu weather station with temperatures recorded further back than 1951 and without success. Does anyone here have any sources of temperatures in this area going back further that they could point me to?

The Zhang paper does reference results using climate model simulations that might be of interest to analyze, but the SI for that paper did not have the temperature data used in the paper nor a reference to where it might be located and linked.

I have downloaded the daily temperature and precipitation for Wudu per Steve M’s instructions and would now like to do comparisons of the temperature and precipitation series.

My problems are with understanding the 15 year uncertainty in assigning particular O18 data that was noted in the Zhang paper comment and excerpted below:

Errors are small, ±1 to ±5 years (2σ), due to high uranium concentrations
(from 5.8 to 10.8 ppm) and low initial thorium contents. The error in assigning a date to a
particular oxygen isotope value is about 15 years because of the uncertainty in relating
the position of the sub-sample used for dating to the position of the sub-samples used for oxygen isotope analysis.

The table below, excerpted in part from the Zhang SI, list in the last column some ages with 2 sigma limits that appear to me to indicate that date resolution is rather fine. On the other hand, when the Zhang authors say that the assignment of a particular date can have an uncertainty of 15 years, I am not certain what this means. Is the 15 years a 2 sigma range? Would not an assignment of a date to a given O18 measure, correct or not, in turn temporally locate the adjacent assignments through the resolution of the dating or are the adjacent date assignments made strictly by distance from the measured data? Could a whole segment of adjacent dates be misplaced by the same amount or could the dates within the segment be “off” by various amounts?

Re: Kenneth Fritsch (#81),
Kenneth, I would think that the age plus precision in the second column of your table is the calculated age for a particular sample submitted for dating. U series can produce ages with very high precisions. The Minnesota lab is amongst the best in the world.

The problem associated with assigning dates to individual isotope values stems from several problems. 1) Different samples are used for the oxygen isotopes and dating; 2) the size of samples used for dating is very much larger than that for the isotope measurement, and 3) it is impossible to correlate or interpolate the position of samples taken for isotopes with those taken for dates.

The problem associated with assigning dates to individual isotope values stems from several problems. 1) Different samples are used for the oxygen isotopes and dating; 2) the size of samples used for dating is very much larger than that for the isotope measurement, and 3) it is impossible to correlate or interpolate the position of samples taken for isotopes with those taken for dates.

Paul, I can comprehend 1 and 2, but I am still attempting to get my mind around 3. The isotope measurements are listed along with an individual year in the Zhang paper, and I, therefore, have the idea that someone has attempted to make an interpolation to an individual year. A larger sample for dating than isotope measurement and yet the dating for that sample can be within plus/minus 1 year.

It’s not that I have any reason (or the background) to doubt any of these explanations or published precisions. I just wish I could visualize it better.

The daily GHCN precipitation data unfortunately has had many missing data points after 1990 and I will now have to go back to my second source that was used for the Wudu temperature data.

After reading a few papers on the dating processes involved here, I have a better feel of why the uncertainties exist. That brings me to reason for questioning in the first place: What is the more exact nature of that uncertainty? The discussion at the Fleitmann 2007 thread has touched on the issue of wiggle matching and whether that is appropriate given the gensis of the dating errors. It would appear that the author, Fleitmann, has consulted statisticians on these matters without a solution. I would simply like to see a more complete explanation of the errors or be pointed to a link that can afford one.

I’ve been re-working speleothem data from a number of locations and comparing them to solar activity proxies for the past ~2000 years. Spannagel is an *extremely* unusual case and I am unsure as to the quality of this temperature reconstruction. If you re-work their data using the above link, and compare this to solar activity (which is availabe at radiocarbon.org – pref. use the intcal04 data set), there seems to be a 50 year shift in the solar activity data. For example, if we look at the Dalton Minimum, it appears to occur around ~1750 at Spannagel, whilst in the solar record it’s known to have onset around 1790. The whole tuning of this record is suspect and the original paper poorly explains how this record has been produced.

If anyone can explain to me why I am getting this i’d be very appreciative. The fact Spannagel record appears to have been tuned to the 14C concentration means almost certainly that the dating is off! Unless i can get hold of an independent age model for Spannagel, I don’t think it will be useful in the slightest.

Apologies for repeating the post in previous threads, but the use of this is a proxy in reconstructions is alarming considering the number of caveats with this record.